
public class binnarysearch {
	
	public static int binarySearch(int[] a, int key) {
		int lo = 0;
        int hi = a.length-1;
        while (lo <= hi) {
            int mid = lo + (hi - lo) / 2;
            if (key < a[mid])
                hi = mid - 1;
            else {
                if (key > a[mid])
                    lo = mid + 1;
                else
                    return mid+1;
            }
         }
        return -1;
    }

}
